package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock {
    private String name;//不同的业务有不同的锁
    private StringRedisTemplate stringRedisTemplate;
    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    private static final String KEY_PREFIX = "lock:" ;
    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-" ;
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }
    @Override
    public boolean tryLock(long timeoutSec) {
        //获取当前线程标识
        String threadId = ID_PREFIX+Thread.currentThread().getId();
        //获取锁
        Boolean success = stringRedisTemplate.opsForValue()
                .setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(success);//避免自动拆箱出现空指针
    }

    public void unLock(){
        //调用lua脚本,解决多条命令原子性问题,实现一致性
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREFIX+Thread.currentThread().getId());
    }
//    @Override
//    public void unLock() {
//        //获取线程标识
//        String threadId = ID_PREFIX+Thread.currentThread().getId();
//        //获取锁中的标识
//        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
//        //判断标识是否一致，只能释放自己的锁,避免redis分布式锁误删问题
//        if (threadId.equals(id)) {
//            //释放锁
//            stringRedisTemplate.delete(KEY_PREFIX + name);
//        }
//    }

}
